The popular heartburn drugs Prilosec and Nexium do not appear to spur heart problems, according to preliminary U.S. and Canadian probes announced yesterday.

The Food and Drug Administration and its Canadian counterpart, Health Canada, began reviewing the drugs, used by tens of millions of people, in May, when manufacturer AstraZeneca provided them an early analysis of two small studies that suggested the possibility of a risk.

Those studies compared treatment of the chronic heartburn known as gastroesophageal reflux disease with either of the two drugs or with surgery, and tracked patients for five to 14 years. The initial analysis found that more patients treated with the drugs had had heart attacks, heart failure or heart-related sudden death.

The FDA followed up on those studies and found that they seemed skewed: Patients who underwent surgery were younger and healthier than those treated by drugs, suggesting that the heart link was a coincidence.

While the studies' designs make safety assessments difficult, many of the participants who developed heart problems had risk factors before starting the drugs, Health Canada said.

The FDA then looked at 14 additional studies of the drugs and found no evidence of heart risks. In a few studies where patients received either medication or a dummy pill, those who took the heartburn drugs had a lower incidence of heart problems.

Does African Dust Affect Atlantic Hurricanes?

Storm scientists are taking a closer look at whether giant dust clouds from the Sahara could join the El Niño phenomenon as a leading indicator of the ferocity of Atlantic hurricane seasons.

Scientists are intrigued by preliminary research showing a direct correlation between the sandy plumes and tropical cyclones.

"What we've seen is: more dust, fewer hurricanes," said William Lau, chief of the Laboratory for Atmospheres at NASA's Goddard Space Flight Center.

The busy and damaging hurricane seasons of 2004 and 2005, which rattled global energy and insurance markets, have heightened interest in storm forecasting and in research on factors that make tropical cyclones either spin into monster storms or wither and die at sea.

El Niño, a warming of eastern Pacific waters, has become a dominant storm indicator because it can flatten an Atlantic hurricane season by increasing the wind shear that can rip apart cyclones.

Cancer Drug Could Cure Dangerous Skin Disease

Four weekly injections of the cancer drug Rituxan may be enough to provide a long-term cure for a rare but potentially fatal skin disorder characterized by blistering lesions that do not heal, French researchers reported.

A study published last year showed similarly impressive improvement using a combination of Rituxan and immune globulin over six months. The new results, reported in the New England Journal of Medicine, suggest that Rituxan alone, over a one-month period, is effective.

The drug, known generically as rituximab, is made by the biotechnology companies Genentech and Biogen Idec, and approved for non-Hodgkin's lymphoma and rheumatoid arthritis.

The drug is sold by Roche AG as MabThera outside the United States, Japan and Canada. Roche sponsored the French study.